Montreal is letting the cash flow in an effort to zap unhealthy products from the St. Lawrence River water supply.

The city will lay down $100 million and the federal government will add $150 million to create an ozone-based water filtration system that will be up and running in three years, removing prescription drugs, plastic microbeads, industrial cleaners and all variety of aquatic impurity.

While the river water is generally considered clean, the chemical component created by pollutants poured into the system have led to some worrisome issues, such as the fear that the female estrogen hormone might gain critical mass in the water supply.

“One thing is certain what the population is using and what we're spilling out into the river doesn't have a very positive effect,” said Richard Fontaine Montreal’s director of wastewater treatment.

The new purification process involves passing oxygen through ultraviolet light, a process which extracts 99 percent of bacteria and between 75 to 85 percent of pharmaceutical drugs and hormones.

But some experts caution that the water will still not be pristine after the process.

“All the chemical that go in the water will not be cleaned by ozonization, such as oil, industrial byproducts, antibiotics and some other drugs,” Martine Chatelain of Eau Secours told CTV Montreal Monday.

Construction on the ozonation plant, to be built at the existing Jean R. Marcotte facility, is scheduled to begin in a few weeks and take three years.

Getting to this point has taken several years, with the initial decision to create an ozonation plant being made in 2008, following by creating technical specifications and determining which companies were able to build such a structure.

The federal and provincial governments are providing the lion's share of the funding, although the final bill for construction is $30 million higher than initially expected.

Officials with the city say the increase is cost is because Montreal is seeking to become a world leader in waste water treatment, and so could not accurately estimate the costs involved.

Montreal city council is expected to vote in favour of granting the contract to Degrement, a subsidiary of Suez Environment, at Monday's council meeting.

Waste water already treated

Drinking water flowing to taps in Montreal is already treated in an ozonation facility to make it safe to use.

The goal of the treatment facility is to reduce, if not eliminate, the hormones, chemical cleaners, and medicinal residues currently flowing into the St. Lawrence River.

Montreal mayor Denis Coderre said the goal is for Montreal to become a world leader in responsible water management.

"We have a great quality of our water right now, but to give it another chance, to make it even better," said Coderre.

He said the waste water Montreal currently eliminates is already treated, but said improvements can be made.

"It's not because it's bad, it's because we want to do it better," said Coderre. "So we are investing in a process to make sure that we enhance, because if there is eventually an issue on the viral and those medicinal substances, hormones, or cosmetic, we have to address that eventually."

Largest ozone waste water facility in the world

The decision to build an ozonation treatment plant for Montreal's effluent was made in 2008 by the Gerald Tremblay administration.

Current waste water treatment only deals with phosphorus and solid matter, and doesn't touch chemicals, hormones, or other materials flushed down toilets.

The ozonation plant should eliminate 95 percent of these materials, making the water in the St. Lawrence cleaner and creating a healthier environment for fish and other riparian animals.

Once completed the Jean R. Marcotte facility should produce 57 tonnes of ozone each day, at a yearly operation cost of $9 million.